1. Field of the Invention
The present invention relates to an apparatus for inspecting and detecting defects of rubbing cloths and a rubbing apparatus with the same, and more particularly, to an apparatus for inspecting for defects of a rubbing cloth which can rapidly and precisely detect the defect of the rubbing cloth by using a camera, and a rubbing apparatus having the same.
2. Description of the Background Art
With the growth of the information society, a liquid crystal display device, which is one of a variety of information display devices, acquires greater importance.
Notably, the liquid crystal display device has advantages of small size, light weight and low power consumption. The liquid crystal display device has gradually expanded its applications and has become a substitute for a cathode ray tube (CRT) displays.
The liquid crystal display device includes two glass substrates with liquid crystal molecules injected between the two glass substrates.
The alignment of the liquid crystal molecules injected between the two glass substrates is changed according to an external electrical signal, in order to adjust a light transmitting amount into an appropriate amount.
To attain a specific optical effect of the liquid crystal display device, the liquid crystal molecules must be oriented in a specific direction.
In general, the liquid crystal molecules are locally oriented. Therefore, an organic polymer film directly contacting the liquid crystal molecules is artificially formed on an indium-tin oxide (ITO) electrode to orient the liquid crystal molecules to the specific direction desired. This organic polymer film is called an orientation film.
In the manufacturing process of the liquid crystal display, a rubbing process is carried out to form orientation grooves on the surface of the orientation film.
The rubbing process wraps a rubbing cloth made of a synthetic fiber such as rayon or nylon around a roller, and makes the roller contact the orientation film to rub against the surface of the orientation film. As a result, the orientation grooves are formed on the surface of the orientation film with a uni-directional alignment over a predetermined level and a pretilt angle existing in a predetermined range.
In the rubbing process, defects in the rubbing cloth mostly result from a loosened part from the rubbing cloth foreign objects and substances sticking to the rubbing cloth, or non-uniform thickness of the rubbing cloth.
Normally, an inspector inspects the rubbing cloth for the defect by his/her experience. However, it takes a lot of effort and time to inspect the rubbing cloth for the defect.
In addition, each inspector has their own standards for inspecting the rubbing cloth for the defect, which reduces accuracy of the inspection.